package com.yami.shop.api.config;

import com.google.zxing.*;
import com.google.zxing.client.j2se.BufferedImageLuminanceSource;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
import sun.misc.BASE64Encoder;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Base64;
import java.util.Hashtable;

/**
 * 二维码生成工具类
 * Created by jason on 2018/11/28 0028.
 */
public final class QRCodeUtil {

	/**
	 * 生成包含字符串信息的二维码图片
	 * @param content 二维码携带信息
	 * @param qrCodeSize 二维码图片大小
	 * @param imageFormat 二维码的格式
	 * @throws WriterException
	 * @throws IOException
	 */
	public static String createQrCode( String content, int qrCodeSize, String imageFormat) throws WriterException, IOException {

		QRCodeWriter qrCodeWriter = new QRCodeWriter();
		BitMatrix bitMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, 900, 900);

		bitMatrix = deleteWhite(bitMatrix);

		ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
		MatrixToImageWriter.writeToStream(bitMatrix, "PNG", outputStream);

		Base64.Encoder encoder = Base64.getEncoder();

		String text = encoder.encodeToString(outputStream.toByteArray());

		return "data:image/png;base64,"+text;
	}

	private static BitMatrix deleteWhite(BitMatrix matrix) {
		int[] rec = matrix.getEnclosingRectangle();
		int resWidth = rec[2] + 1;
		int resHeight = rec[3] + 1;

		BitMatrix resMatrix = new BitMatrix(resWidth, resHeight);
		resMatrix.clear();
		for (int i = 0; i < resWidth; i++) {
			for (int j = 0; j < resHeight; j++) {
				if (matrix.get(i + rec[0], j + rec[1]))
					resMatrix.set(i, j);
			}
		}
		return resMatrix;
	}


	/**
	 * 创建二维码输入流
	 * @param content		二维码内容
	 * @param qrCodeSize	二维码尺寸
	 * @param imageFormat	图片格式
	 * @param response		响应给页面
	 */
	public static void createQrCodeStream(String content, int qrCodeSize, String imageFormat, HttpServletResponse response) throws IOException, WriterException {
		//设置二维码纠错级别ＭＡＰ
		Hashtable<EncodeHintType, ErrorCorrectionLevel> hintMap = new Hashtable<EncodeHintType, ErrorCorrectionLevel>();
		hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);  // 矫错级别
		QRCodeWriter qrCodeWriter = new QRCodeWriter();
		//创建比特矩阵(位矩阵)的QR码编码的字符串
		BitMatrix byteMatrix = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, qrCodeSize, qrCodeSize, hintMap);
		// 使BufferedImage勾画QRCode  (matrixWidth 是行二维码像素点)
		int matrixWidth = byteMatrix.getWidth();
		BufferedImage image = new BufferedImage(matrixWidth-200, matrixWidth-200, BufferedImage.TYPE_INT_RGB);
		image.createGraphics();
		Graphics2D graphics = (Graphics2D) image.getGraphics();
		graphics.setColor(Color.WHITE);
		graphics.fillRect(0, 0, matrixWidth, matrixWidth);
		// 使用比特矩阵画并保存图像
		graphics.setColor(Color.BLACK);
		for (int i = 0; i < matrixWidth; i++){
			for (int j = 0; j < matrixWidth; j++){
				if (byteMatrix.get(i, j)){
					graphics.fillRect(i-100, j-100, 1, 1);
				}
			}
		}
		// 返回给页面
		OutputStream outputStream= response.getOutputStream();
		// 关流
		try {
			ImageIO.write(image, imageFormat, outputStream);
		} finally {
			outputStream.close();
		}
	}

	/**
	 * 读二维码并输出携带的信息
	 */
	public static void readQrCode(InputStream inputStream) throws IOException{
		//从输入流中获取字符串信息
		BufferedImage image = ImageIO.read(inputStream);
		//将图像转换为二进制位图源
		LuminanceSource source = new BufferedImageLuminanceSource(image);
		BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
		QRCodeReader reader = new QRCodeReader();
		Result result = null ;
		try {
			result = reader.decode(bitmap);
		} catch (ReaderException e) {
			e.printStackTrace();
		}
		System.out.println(result.getText());
	}


	/**
	 * 测试代码
	 * @throws WriterException
	 */
	public static void main(String[] args) throws IOException, WriterException {

		//String qrCode =  createQrCode("D:\\qrcode.jpg","http://www.baidu.com",900,"JPEG");
		//System.out.println("输出的二维码为"+qrCode);
		//readQrCode(new FileInputStream(new File("E:\\qrcode.jpg")));
	}
}
